A radiation detector configured to image radiation is used in the medical field and other various fields. Description will be given of a concrete construction of such the radiation detector. A conventional radiation detector 60 includes, as illustrated in FIG. 15, an amorphous selenium layer 51 configured to convert radiation into a pair of carriers of electron and positive hole; high resistance films 52, 57 laminated so as to cover both faces of the amorphous selenium layer 51; an active matrix substrate 54 configured to contact the high resistance film 57 and having a thin-film transistor, an electric wire, and an interlayer insulating layer formed on a glass substrate; an electrode layer 53 laminated on the high resistance film 52; an insulating resin layer 55 configured to cover the amorphous selenium layer 51, the high resistance film 52, and the electrode layer 53; and a glass plate 56 configured to cover the insulating resin layer 55. For details, see Patent Literatures 1, 2, 3, and 4.
Such the radiation detector 60 has the both faces covered with the glass plate. This eliminates warp of the radiation detector 60 resulting from variations in temperature. Consequently, crack is prevented from occurring in an interior of the radiation detector 60.
The high resistance film 52 has a function as carrier selection that blocks charge injection from the electrode layer 53. In addition, high resistance film 52 has a function of separating the amorphous selenium layer 51 away from the insulating resin layer 55. The insulating resin layer 55 is provided for electrically shielding the electrode layer 53.
The wire 58 is provided for applying electric potential of a ground to each of the detecting elements in the radiation detector 60. The wire 58 is electrically separated away from the electrode layer 53 via the high resistance film 52 and the amorphous selenium layer 51. This causes no short between the electrode layer 53 and the wire 58.
FIG. 16 illustrates an end portion of the radiation detector 60. As illustrated in FIG. 16, the amorphous selenium layer 51 has an end portion 51a with a film thickness thereof gradually decreasing and a center portion 51b with a film thickness not decreasing. The wire 58 mentioned above is also connected to the end portion of the radiation detector 60. The wire 58 in the end portion of the radiation detector 60 is provided in a position corresponding to the end portion 51a of the amorphous selenium layer 51. With the conventional construction, the high resistance film 52 also covers the end portion 51 of the amorphous selenium layer 51. On the other hand, no electrode layer 53 is provided over the end portion 51a of the amorphous selenium layer 51.